This invention relates to a rotating airfoil system such as a rotor or propeller, and more particularly, the invention relates to a messaging system for transmitting communications between an airframe and the rotating airfoil assembly.
Rotating airfoil systems transmit power from the airframe to the rotating airfoil assembly to provide power to the rotating airfoil assembly systems such as blade pitch angle actuators and blade heaters. In addition to simply powering these systems, it is desirable to selectively control the systems and monitor their status to ensure desired operation. For example, propellers are most efficient when their blade pitch angle is adjusted to accommodate for air speed, altitude, and thrust requirements. When multiple propellers are employed on one airframe, it is also important to match the performance of the propellers to minimize noise and vibration. Additionally, a number of techniques are employed to measure blade pitch angle. The most accurate generally involves sensors mounted on the propeller blades. These devices measure rotation of the blade with respect to the relatively fixed propeller barrel. The expense and difficulty of reliably transmitting this information between the airframe and airfoil assembly presents numerous problems.
As another example, propeller blade heaters are controlled through slip rings to turn the blade heaters on and off to de-ice the airfoil. Reports on system operation of the blade heaters are also transmitted across the slip rings. However, the slip rings are difficult and expensive to maintain and lack the practical ability to provide redundancy due to their size, which is always desirable for critical aircraft systems. To this end, it is desirable to eliminate the slip rings to reduce the maintenance and expense associated therewith. It is also desirable to provide a redundant messaging system that may be used to send and receive messages between the airframe and rotating airfoil assembly.
The present invention provides a messaging system for a rotating airfoil system including a stationary structural member supporting a shaft that is rotatable about an axis. An airfoil assembly is supported by the shaft. A first arcuate coil assembly is supported on the structural member and is arranged at least partially about the shaft. A second arcuate coil assembly is supported on the airfoil assembly adjacent to the first arcuate coil assembly and is rotatable relative thereto. One of the coil assemblies provides a magnetic field having an inductance with an electronic message. The inductance of the one coil assembly produces a voltage containing the message in the other coil assembly. The message may be demodulated from the voltage. In this manner, messages may be sent to and from airfoil assembly systems such as blade heaters and blade pitch actuators.
Accordingly, the above invention provides a rotating airfoil system that eliminates the use of slip rings while providing redundant messaging across the airframe and airfoil assembly.